The present invention relates to railcar moving vehicles of the type which are adapted for travel alternatively on railroad tracks on rail wheels or on the ground or other surface on ground wheels for moving railcars when the vehicle is on the rails.
Railcar moving vehicles of this type have been provided for moving railcars without the need for large, expensive locomotives and the like. Such vehicles are capable of operating both in a rail travel mode on the rails on which the cars are moved or in the ground travel mode for transferring the vehicle between tracks.
One such prior railcar is shown, by way of example, in U.S. Pat. No. 3,892,187. The railcar moving vehicle disclosed in that patent includes two pairs of spaced rail wheel sets which are adapted to ride upon the rails and two pairs of ground wheel sets for propelling the vehicle on the ground off of the rails. In this patent, hydraulic cylinders raise and lower the rail wheel sets such that either the rail wheel sets are in contact with the rails in the rail travel mode or the ground wheels are in contact with the ground in the ground travel mode. The ground wheels are mechanically driven by a differential and the rail wheels are driven by chains and sprockets off of the ground wheels.
In U.S. Pat. No. 4,067,259 a railcar moving vehicle is disclosed which also includes two pairs of rail wheel sets and two pairs of road wheel sets. The ground wheel sets, rather than the rail wheel sets, are moved up and down so that the vehicle is operable either in the rail travel mode in which the rail wheel sets are in contact with the rails or in the ground travel mode in which the ground wheel sets are in contact with the ground. This Letters Patent further discloss a weight transfer coupler in which a substantial portion of the weight of the railcar which is being moved is transferred and added to the weight of the railcar moving vehicle and its rail wheels to improve the traction or tractive effort of the vehicle when it is in the rail travel mode. In this railcar, the rail wheels are mechanically driven and the ground wheels are driven by driving hubs on the rail wheels which engage the ground wheel tires.
In U.S. Pat. No. 4,167,142 a railcar moving vehicle is shown which also has two pairs of rail wheel sets and two pairs of ground wheel sets. Again, the ground wheels are movable up and down such that the rail wheels are positioned on the rails in the rail travel mode and the gound wheels are positioned on the ground in the ground travel mode. As in the last previously mentioned Letters Patent, this Letters Patent also discloses a weight transfer coupler for transferring some of the weight of the railcars being moved to the vehicle rail wheels to improve the traction or tractive effort thereof.
Each of these aforementioned prior railcar moving vehicles realizes a number of advantages.
One advantage resides in the weight transfer coupler as previously mentioned. These couplers transfer a substantial portion of the weight of the railcars being moved to the railcar moving vehicle and to its rail wheels. Such weight transfer substantially increases the traction or tractive effort of the rail wheels on the rails and improves its pulling capability to the extent that relatively smaller and less expensive railcar moving vehicles have pulling capabilities which would otherwise be available only in larger switching vehicles. Another advantage of such prior railcar moving vehicles is that the railcar moving vehicles may be transferred between different tracks without the need for switches. Still another advantage of such prior railcar moving vehicles is that there is no need for the vehicle operator to leave the cab, either to accomplish coupling of the vehicle to the railcars to be moved or when transferring the vehicle itself on the ground between different sets of tracks. Still another advantage of such prior railcar moving vehicles is that the conversion from the ground travel mode to the rail travel mode or vice versa may be quickly accomplished and the vehicles are highly maneuverable when on the ground. The use of such prior railcar moving vehicles results in a substantial minimization of trackage, switches and real estate at its location of operation, and minimum work crew time and demurrage is also realized.
The present invention is directed to an improved railcar moving vehicle and control means therefor which realizes all of the aforementioned advantages of the prior railcar moving vehicles which have just been described. In addition, the railcar moving vehicle and control means therefor incorporating the principles of the present invention realizes several additional important advantages not present in such prior vehicles.
In a railcar moving vehicle and control means therefor incorporating the principles of the present invention, a substantial increase in the tractive effort or traction over the prior railcar moving vehicles in the rail travel mode is realized. Such increased tractive effort is particularly advantageous where a number of railcars are to be moved at the same time, where the railcars are heavily loaded, where traction of the rail wheels is lost, for example, if the rails are wet, or where the railcars must be moved up a grade. In a railcar moving vehicle and control means therefor incorporating the principles of the present invention, the ground wheels which are already present on the vehicle may be placed into advantageous use during the rail travel mode to realize this additional traction or tractive effort and only a minimum of additional control components need be provided to achieve this result. In several of the embodiments of railcar moving vehicle incorporating the principles of the present invention, complex ground wheel differentials for powering the ground wheels or elaborate mechanical drives from the rail wheels may be eliminated by employing individual hydrostatic units on the powered ground wheels, thus improving the operation and maneuverability of the railcar moving vehicle and simplifying its construction.
In one principal aspect of the present invention, a railcar moving vehicle is capable of travel in a first rail travel mode on flanged rail wheels on the rails of a railway track and in a second ground travel mode on ground wheels. The vehicle includes a prime mover, front and rear rail wheel sets, at least one set of which is powered by the prime mover, front and rear ground wheels aligned in the same direction as the rail wheels and drive means powering at least one of the front and rear ground wheels. Control means moves at least one of the front and rear rail wheel sets and the front and rear ground wheels relative to the other so as to interchangeably convert the vehicle from one of the travel modes to the other. The improvement in such railcar moving vehicle comprises means for moving at least one of the rail wheel sets and the ground wheels relative to each other to shift the vehicle to a third rail traction assist travel mode in which each of the rail wheel sets is in contact with the rails and the vehicle is powered by at least some of the rail wheel sets, and the powered ground wheels also simultaneously drivingly frictionally engage a surface with sufficient force to increase the traction of the vehicle.
In another principal aspect of the present invention, in the aforementioned railcar moving vehicle, the ground wheels are moved relative to the rail wheels to drivingly frictionally engage the surface to increase the traction of the vehicle when the vehicle is in the third rail traction assist travel mode.
In still another principal aspect of the present invention, in the aforementioned railcar moving vehicles, the ground wheels which drivingly frictionally engage the surface comprise a pair of ground wheels spaced from each other in a direction perpendicular to the direction of movement of the vehicle and said drive means power both of the pair of last mentioned ground wheels independently of each other and of the rail wheel sets by independent hydrostatic means.
In still another principal aspect of the present invention, in all but the last mentioned railcar moving vehicle, the ground wheels which frictionally engage the surface comprise a pair of ground wheels spaced from each other in a direction perpendicular to the direction of movement of the vehicle and both of the pair of last mentioned ground wheels are powered from at least one of the rail wheel sets by said drive means.
In still another principal aspect of the present invention, the surface which is frictionally engaged by the ground wheels in the rail traction assist travel mode of the aforementioned railcar moving vehicles may be either the bed of the railway track or the surfaces of the rails themselves.
In still another principal aspect of the present invention, the aforementioned railcar moving vehicles may include yielding means for permitting the ground wheels which drivingly frictionally engage the surface to elevate at obstacles on the surface, but remain in frictional driving contact with such obstacles.
In still another principal aspect of the present invention, the aforementioned railcar moving vehicles include coupler means on the vehicle adjustably supporting and transferring weight from a railcar coupled to the vehicle to at least one of the rail wheel sets in the third rail traction assist travel mode.
In still another principal aspect of the present invention, control means are provided for controlling the wheel position of a railcar moving vehicle for travel in a first rail travel mode on the rails of a railway track on front and rear flanged rail wheel sets at least some of which are powered and in a second ground travel mode on front and rear ground wheels at least one of which is also powered. The control means moves at least one of the front and rear flanged rail wheel sets and front and rear ground wheels relative to the other so as to interchangeably convert the vehicle from one of the travel modes to the other. The improvement in such control means comprises means for moving at least one of the rail wheel sets and ground wheels relative to each other to shift the vehicle to a third rail traction assist travel mode in which each of the rail wheel sets is in contact with the rails and the vehicle is powered by at least some of the rail wheel sets, and powered ones of the ground wheels also simultaneously drivingly frictionally engage a surface with sufficient force to increase the traction of the vehicle.
In still another principal aspect of the present invention, the ground wheels are moved relative to the rail wheel sets to drivingly frictionally engage the surface for increasing the traction of the vehicle when the vehicle is in the third rail traction assist travel mode.
In still another principal aspect of the present invention, the aforementioned control means includes force reducing means for reducing the force with which the powered ones of the ground wheels drivingly frictionally engage the surface from the force which is exerted by the ground wheels upon the ground when the vehicle is in the ground travel mode.
In still another principal aspect of the present invention, the aforementioned control means also includes yielding means for permitting the ground wheels which drivingly frictionally engage the surface to elevate at obstacles on the surface, but to remain in frictional driving contact with the obstacles.
In still another principal aspect of the present invention, a railcar moving vehicle is capable of travel in a first rail travel mode on flanged rail wheels on the rails of a railway track and in a second ground travel mode on ground wheels. The vehicle includes a prime mover, front and rear rail wheel sets, at least one of which is powered by the prime mover, and front and rear ground wheels at least one of which is also powered. Control means moves at least one of the front and rear rail wheel sets and the front and rear ground wheels relative to the other so as to interchangeably convert the vehicle from one of the travel modes to the other. The improvement in such railcar moving vehicle comprises drive means on the powered ground wheels to power at least a pair of the ground wheels independently of each other and of the rail wheel sets.
In still another principal aspect of the present invention, in the last mentioned railcar moving vehicle the drive means whic powers the pair of ground wheels are independent hydrostatic means.
In still another principal aspect of the present invention, a vehicle for travel on flanged rail wheels on the rails of a railway track includes a prime mover and front and rear rail wheel sets at least one of which is powered by the prime mover. The improvement in such vehicle comprises at least one wheel in addition to the rail wheel sets and drive means for powering the additional wheel. Control means moves at least one of the rail wheel sets and the additional wheel relative to each other to shift the vehicle to a rail traction assist travel mode in which each of the rail wheel sets is in contact with the rails and the vehicle is powered by at least some of the rail wheel sets, and the powered additional wheel also simultaneously drivingly frictionally engages a surface with sufficient force to increase the traction of the vehicle.
In still another principal aspect of the present invention, the aforementioned additional wheel is moved relative to the rail wheels to frictionally engage the surface for drivingly increasing the traction of the vehicle when the vehicle is in the rail traction assist travel mode.
In still another principal aspect of the present invention, in the aforementioned vehicles the additional wheel which drivingly frictionally engages the surface comprises a pair of additional wheels spaced from each other in a direction perpendicular to the direction of movement of the vehicle and the drive means powers both of the last mentioned additional wheels independently of each other and of the rail wheel sets.
In still another principal aspect of the present invention, the surface which is frictionally engaged by the additional wheel or wheels in the rail traction assist travel mode of the aforementioned vehicles may be either the bed of the railway track or the surfaces of the rails themselves.
In still another principal aspect of the present invention, the aforementioned vehicles may include yielding means for permitting the additional wheel or wheels which drivingly frictionally engage the surface to elevate at obstacles on the surface, but remain in frictional driving contact with such obstacles.
In still another principal aspect of the present invention, the aforementioned vehicles include coupler means on the vehicle adjustably supporting and transferring weight from a railcar ooupled to the vehicle to at least one of the rail wheel sets in the rail traction assist travel mode.
These and other objects, features and advantages of the present invention will become more readily understood upon a consideration of the following detailed description.